Modify property value of the objects in list using Java 8 streams

Question

I have a list of Fruit objects in ArrayList and I want to modify fruitName to its plural name   Refer the example    Data  AllArgsConstructor  ToString class Fruit        long id      String name      String country     List lt Fruit gt  fruits   Lists newArrayList    fruits add new Fruit 1L   Apple    India     fruits add new Fruit 2L   Pineapple    India     fruits add new Fruit 3L   Kiwi    New Zealand      Comparator lt Option gt  byNameComparator    e1  e2  - gt  e1 getName   compareToIgnoreCase e2 getName      fruits   fruits stream   filter fruit - gt   India  equals fruit getCountry                  sorted byNameComparator  collect Collectors toList      List lt Fruit gt  fruitsWithPluralNames   Lists newArrayList    for  Fruit fruit   fruits        fruit setName fruit getName      s        fruitsWithPluralNames add fruit      System out println fruitsWithPluralNames       which prints  Fruit id 1  name Apples  country India   Fruit id 2  name Pineapples  country India   Fruit id 3  name Kiwis  country New Zealand      Do we have any way to achieve same behavior using Java 8 streams

User · Accepted Answer

If you wanna create new list  use Stream map method   List lt Fruit gt  newList   fruits stream        map f - gt  new Fruit f getId    f getName      s   f getCountry          collect Collectors toList      If you wanna modify current list  use Collection forEach   fruits forEach f - gt  f setName f getName      s

User · Answer

You can use peek to do that   List lt Fruit gt  newList   fruits stream        peek f - gt  f setName f getName      s         collect Collectors toList

User · Answer

You can use just forEach  No stream at all   fruits forEach fruit - gt  fruit setName fruit getName      s

User · Answer

You can do it using streams map function like below  get result in new stream for further processing   Stream lt Fruit gt  newFruits   fruits stream   map fruit - gt   fruit name   s   return fruit             newFruits forEach fruit- gt               System out println fruit name

User · Answer

just for modifying certain property from object collection you could directly use forEach with a collection as follows  collection forEach c - gt  c setXyz c getXyz    a

[java-8] Modify property value of the objects in list using Java 8 streams

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